The present invention relates to a magnetic tape and a method for manufacturing said magnetic tape, and in particular to a method for shaping and fabricating end surfaces of a magnetic tape by laser and also to a magnetic tape manufactured by said method.
A magnetic tape for video tape recorder is manufactured as follows: a magnetic film of 3-layer structure comprises a magnetic layer and a back layer coated on each side of a support layer called a base layer, and it is cut off to a predetermined dimension by a cutting process called slitter process.
In the slitter process, the magnetic film is cut off using a metal rotary cutter. The rotary cutter has an upper blade and a lower blade. Depending on engaging dimensions of these two blades and on cutting speed, cutting surface may be entirely different from the surface as originally desired, e.g. the magnetic layer may protrude more than the other layer on the cutting surface of the upper blade side, or the back layer may protrude more than the other layer on the cutting surface of the lower blade side.
The problems at the cutting as described above may cause further troubles: When the tape is used in practical application, the protruded portion of the magnetic tape may be turned to thread-like chips as the protruded portion is scraped off by guide roller and the like of the magnetic tape, thereby causing filling-up of magnetic head, or drop-out of signal may occur, and the desired voltage cannot be obtained in recording or reproducing signals, or trouble may occur to the running of tape due to deterioration in rolling shape or conditions even when scraping does not occur and tape edge may be seriously damaged and recording cannot be achieved on that portion. In particular, protrusion of the back layer causes scraping of tape to thread-like chips, and it is necessary to eliminate this protrusion by some method.